Piston-position indicator



Jan. 20,4931, T. A. MURPHY.

vPIsToN POSITION INDICATGR Filed Aug. 29. 1930` v 7@ ra//VEY www;

l io

r .employed for indicating the y Lpiston in an engine cylinder, and anobject Patented Jan.

master r Seite' i Appiiann flied Augusiea, 1930.7 sriaignoffivejvio.

rMy invention relates to the classof deviceS positive in its action, and that'may be readily attached in place for operation.

@ne form of an indicatorl embodying finy'V invention and in the construction' and use of i accompanying'drawings,in whichff c ,section throughl the-r same. Y. n

Figure?) shows the indicator attached tofv the cylinder of anengine andthe position" carbon by burning,

, Figure l is a .sidevew-of myimproved indicator-.Q 1 a ,f g,

Figure is a view in 'central lengthwise ot the indicator rod at the completion'of the compression stroke of the piston. A

Figure fi is a similar view but showing the positionctthe indicator rod immediately ol lowing the end ot-thecompression' strokeL` It `isides'irable in many instances to v know when the piston 10i an engine cylinder' .isv

-iuSt at the end of itscompression stroke as, `:tor

instance, when itis desired tolremovethe as the'position of theV piston at this time completely protects theL Again,

i'1 chamber 7 and the valve 9 will at fonce drop lto itsseat thus indicating theend 'of the com-f walls of the cylinder from' injury.

tion is taking place properly.v My device,

illustrated and described herein, is so ar-V vranged that theend of the compression stroke V*tothe body as by Vscrew threads,Y this,

ot the piston in a cylinder maybe certainly and readily determinedthe instant it occursj Suchdevice comprises a body. 5that` is threaded to it the spark plug opening for Anindicator tube 6 is secured means of vinter-engaging tube having a chamberf?y therein through whichv an indicator rod 8 extends, the lcwerl end of the rodhaving a valve?) fitting apassage fl() extending to the the cylinder.,

end of the -tube and'communicating'with aV passage ll extendinginwardly from the end ofthe body position of a Y ormyinveiition, among others, is to provide an indicator for thispurpose that shallfbe .v

thefrod 8 proj ects. *l

V,v/ith;respect .to that of the stem is @triggery `atedliereinn A f In the; actual rv structure the 'stem or; rod 8 beso fitted tothe opening '13 as tofpermit g il l" a v"slightvent through suchopeninggr i l g.

preventrthestem or rod from:risingbyArea-v E soirot 'pressure Within theengine Q cylinder, f VLQair1s,t.othe Valve 9.

' clearance, hcmfeve'r,"y will. notfbe 1suchlfas' 4to is applied tothe lspark plug opening'lL-in an createdthereby will bee'Xe-rted against the within'thechamber 7, the stem or rod 8 being moved outwardlybeyond theend of the cap l2.v A 'steady movement'being imparted to vithe crank shaft the stem'S will movesteadily Voutward until the Ypiston 16 reaches @the end got fits .compression .c stroke.-A rlhe V'pressure Y within vthe cylinder 'ceasing at this instant, a

suiiicient vent Vwill' take'place through the f` A i opening -lto relieve thev pressure in the Vpression stroke ot the piston.

Infaccordance with the provisions ot thef patent statutes l have described the principles A ot Aoperation of myinvention, together with!` .Y

THOMAS A. MURPHY; on Minnnrfrcwinoemincrrcni,iissieivon yor ONE-'HALF Tov l *f orfPORTLAND,coNNyEcTicnmff fjvlcap l2 is` screw thread'edjly engaged with" f the outer endjofthetube@ thiscaphavii'igairopening 13 throughwhich the 'steinfoi'kv 'f The sizeof this opening i i Inthe operation'oflthe devicethe 'valve 9 and the'latter will be `forced outwardly the device whichlnow consider to represent A the best embodiment'thereoi'; butjv'desir'e tor4 y `il'iave it understood that the deviceshown is"Y 'onlyillustrative,l and that the invention may be carriedv out other means andappli'ed to f sie luses lother than those above set out,l I s I claim :.5

f piston position indicatorl including a' 'i memberhaving a chamber thereinand adapted tobe attached to an engine cylinder vtor chamber' in the engine cylinder,a valve. lo.-`

vof said chamber, and means for pi-ovidiiig` a es f communication of said chamber .f with the *cated in said chamber, astem .projectingoutj` 'i r lvent to said chamber insuflicient to prevent i .movement of the valve by reason of the pressure in the engine cylinder. l o

2. A piston position indicator including a member having a chamber therein and adaptedto be attached to an engine cylinder for communciation of said chamber with the chamberin the engine cylinder, a valve 1ocatedin said chamber, a stem projecting out o of lsaid chamber,y the size of said` stem rela# tively to the openingfot-herefor being such vasi to provide a vent insuficient, however, to prevent movement of the valve under `pressure Wit-hin the engine cylinder. Y

3. A piston position indicator includinga f body adapted for attachment Within the spark Y ping opening of a cylinder, a tube projecting from said bodyand havin g a chamber therein With a passage extending from said chamber to the end of the body, a valve located in said j chamber, a cap to close the end ofsaidjchamber, 'a stem projecting from the valvev through said cap, the opening inthe cap and thesize of the stem beingrelative'ly such'asV to provide auvent insufficient, however, to prevent movement ofthe valveunder pressure caused j y by movement of the piston in the` cylinder to its compressionstroke'.v d Y t THOMAS 1A.' MURPHY. l 

